Field of the Invention
The invention generally relates to a communications method and apparatus, and more particularly, to a method to configure additional antennas in single component carrier situation.
Description of the Related Art
Wireless communications systems are widely deployed to provide various telecommunications services such as telephony, video, data, messaging, and broadcast. Typical wireless communications systems may employ multiple-access technologies capable of supporting communications with multiple users by sharing available system resources (e.g., bandwidth, transmitting power). Examples of such multiple-access technologies include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, single-carrier frequency divisional multiple access (SC-FDMA) systems, and time division synchronous code division multiple access (TD-SCDMA) systems.
Carrier Aggregation (CA) improves the data rate of user equipment (UE) by aggregating multiple component carriers for parallel transmission and reception. Carrier aggregation may be enhanced by allowing different Time Division Duplex (TDD) uplink (UL)-downlink (DL) configuration for inter-band carrier aggregation. With such an enhancement, the system can coexist well with the current 3G network and make deployment targeting for different needs easier.
Component carriers may be divided into a primary component carrier (PCC) and a secondary component carrier (SCC). The PCC refers to a carrier that is constantly activated, and the SCC refers to a carrier that may be activated or deactivated according to particular conditions. Activation means that transmission or reception of traffic data may be performed or traffic data is ready for its transmission or reception on the concerned component carrier. Deactivation means that transmission or reception of traffic data is not permitted on the concerned component carrier. The user equipment uses only a single PCC or one or more SCCs along with the PCC.
FIG. 1 is a block diagram of a receiver (or user equipment) in traditional Carrier Aggregation (CA). In FIG. 1 the receiver comprises two antennas R1-R2 and a plurality of processing engines such as Radio Frequency (RF)/Analog Front End (AFE) modules, Digital Front End (DFE) modules, Fast Fourier Transform (FFT) modules, Multiple Input Multiple Output (MIMO) Pre-processors, MIMO detectors and Bit Rate Processing (BRP) modules. When the service network provides two component carriers (CCs) for the transmission of Carrier Aggregation, the upper part of processing engines are configured for one component carrier, and the lower part of the processing engines are configured for the other component carrier. However, when the service network only provide single component carrier (e.g. PCC) for the receiver, the processing engines configured for the other component carrier (e.g. SCC) will be in an idle mode. Therefore, the processing engines in the idle mode are not operating efficiently.